Pub Date : 2026-01-19DOI: 10.1016/j.optcom.2026.132928
Chupeng Lu , Xiaoyang Li , Xinyu Yang , Xinhang Xu , Hang Jiang , Tao Geng , Libo Yuan
In this paper, a polarization-multiplexed long-period fiber grating (LPFG) sensor capable of simultaneous curvature, torsion, and temperature measurements is proposed for fiber-based shape sensing. The sensor is fabricated by CO2 laser inscription on a pre-twisted composite fiber structure comprising a polarization-maintaining fiber (PMF) fusion-spliced between two single-mode fibers (SMFs). The synergistic effects of pre-twist and CO2 laser induced thermal stress significantly modify the internal stress distribution of the PMF, thereby enhancing its elliptical birefringence. This enhancement results in pronounced polarization-dependent resonant wavelengths and sensitivities. The fabricated PMF-LPFG exhibits distinct resonant wavelengths of 1547.4 nm and 1525.6 nm when the input light is aligned with the slow axis (0°) and fast axis (90°), respectively. Experimental results demonstrate that the proposed sensor achieves a maximum torsion sensitivity of 2.24 nm/(rad/m) and a maximum curvature sensitivity of 45.68 nm/m−1 at 0° polarization, with a corresponding temperature sensitivity of 108.9 p.m./°C. Owing to its compact structure, high sensitivity, and polarization-multiplexing capability, the proposed sensor demonstrates strong potential for practical three-dimensional shape sensing applications.
{"title":"Polarization-multiplexed fiber grating sensor with enhanced birefringence for shape sensing applications","authors":"Chupeng Lu , Xiaoyang Li , Xinyu Yang , Xinhang Xu , Hang Jiang , Tao Geng , Libo Yuan","doi":"10.1016/j.optcom.2026.132928","DOIUrl":"10.1016/j.optcom.2026.132928","url":null,"abstract":"<div><div>In this paper, a polarization-multiplexed long-period fiber grating (LPFG) sensor capable of simultaneous curvature, torsion, and temperature measurements is proposed for fiber-based shape sensing. The sensor is fabricated by CO<sub>2</sub> laser inscription on a pre-twisted composite fiber structure comprising a polarization-maintaining fiber (PMF) fusion-spliced between two single-mode fibers (SMFs). The synergistic effects of pre-twist and CO<sub>2</sub> laser induced thermal stress significantly modify the internal stress distribution of the PMF, thereby enhancing its elliptical birefringence. This enhancement results in pronounced polarization-dependent resonant wavelengths and sensitivities. The fabricated PMF-LPFG exhibits distinct resonant wavelengths of 1547.4 nm and 1525.6 nm when the input light is aligned with the slow axis (0°) and fast axis (90°), respectively. Experimental results demonstrate that the proposed sensor achieves a maximum torsion sensitivity of 2.24 nm/(rad/m) and a maximum curvature sensitivity of 45.68 nm/m<sup>−1</sup> at 0° polarization, with a corresponding temperature sensitivity of 108.9 p.m./°C. Owing to its compact structure, high sensitivity, and polarization-multiplexing capability, the proposed sensor demonstrates strong potential for practical three-dimensional shape sensing applications.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"607 ","pages":"Article 132928"},"PeriodicalIF":2.5,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-18DOI: 10.1016/j.optcom.2026.132927
Daehyun Kim , Hayato Otsu , Masato Tsujiguchi , Naoki Fujita , Maria Vanessa Balois-Oguchi , Kotaro Kajikawa
Novel designs of a Kretschmann-type surface plasmon resonance (SPR) platform are presented, in which surface plasmons are excited by light incident parallel or perpendicular to the prism-metal interface, using a prism with a high refractive index of approximately 2.0. These designs enable us to miniaturize the optical setup, as the SPR condition can be achieved without the need for a rotation mechanism. The refractive index of water–ethanol mixtures with various mixture ratios was measured, and the formation process of a self-assembled monolayer was observed to demonstrate the adequacy of our design.
{"title":"Surface plasmon resonance excited using Kretschmann configuration with high refractive-index-prism","authors":"Daehyun Kim , Hayato Otsu , Masato Tsujiguchi , Naoki Fujita , Maria Vanessa Balois-Oguchi , Kotaro Kajikawa","doi":"10.1016/j.optcom.2026.132927","DOIUrl":"10.1016/j.optcom.2026.132927","url":null,"abstract":"<div><div>Novel designs of a Kretschmann-type surface plasmon resonance (SPR) platform are presented, in which surface plasmons are excited by light incident parallel or perpendicular to the prism-metal interface, using a prism with a high refractive index of approximately 2.0. These designs enable us to miniaturize the optical setup, as the SPR condition can be achieved without the need for a rotation mechanism. The refractive index of water–ethanol mixtures with various mixture ratios was measured, and the formation process of a self-assembled monolayer was observed to demonstrate the adequacy of our design.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"607 ","pages":"Article 132927"},"PeriodicalIF":2.5,"publicationDate":"2026-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.optcom.2026.132926
Yi Qin , Yueyou Li , Qiong Gong , Liming Zhang , Chao Liu , Wei Liu
The scattering-imaging-based encryption (SIBE) employs spatially incoherent illumination and exploits the optical memory effect (OME) inherent in the scattering media, offering significant benefits such as immunity to speckle noise and highly compact system designs. Nevertheless, the OME imposes a constraint on the maximum plaintext size that the cryptosystem can process in a single acquisition. The present research indicates that a well-trained deep neural network (DNN) is potentially able to retrieve the plaintext directly from the ciphertext. However, due to its large size, the DNN is inconvenient for transmission and distribution, making it unsuitable for use as the secret key. In this paper, we propose a cross-modality SIBE (CM-SIBE) approach by employing deep learning. We construct two encryption schemes: a real SIBE (R-SIBE) and a virtual SIBE (V-SIBE). For convenience, their corresponding ciphertexts and PSFs are denoted as R-Ciphertext and R-PSF for the real scheme, and V-Ciphertext and V-PSF for the virtual one, respectively. We encrypt the plaintext with the R-SIBE and take the R-Ciphertext as the final ciphertext. However, we take the V-PSF as the secret key. For successful decryption, we train a DNN to convert the R-Ciphertext into its corresponding V-Ciphertext; the two ciphertexts are derived from the same plaintext. It is important to note that the V-PSF acts as the sole secret key, while the DNN serves as an auxiliary tool. For decryption, an authorized user first transforms the ciphertext into the V-Ciphertext using the DNN. Subsequently, the user deconvolves the V-Ciphertext with the V-PSF to retrieve the original plaintext. Our CM-SIBE ensures high-quality decryption of large-sized plaintexts that surpass the OME limit of the diffuser, while also circumventing the need for a bulky DNN as the secret key. Furthermore, our method is robust against known ciphertext-only (COA), while also demonstrating high resilience to noise and occlusion.
{"title":"Cross-modality scattering-imaging-based encryption by deep learning","authors":"Yi Qin , Yueyou Li , Qiong Gong , Liming Zhang , Chao Liu , Wei Liu","doi":"10.1016/j.optcom.2026.132926","DOIUrl":"10.1016/j.optcom.2026.132926","url":null,"abstract":"<div><div>The scattering-imaging-based encryption (SIBE) employs spatially incoherent illumination and exploits the optical memory effect (OME) inherent in the scattering media, offering significant benefits such as immunity to speckle noise and highly compact system designs. Nevertheless, the OME imposes a constraint on the maximum plaintext size that the cryptosystem can process in a single acquisition. The present research indicates that a well-trained deep neural network (DNN) is potentially able to retrieve the plaintext directly from the ciphertext. However, due to its large size, the DNN is inconvenient for transmission and distribution, making it unsuitable for use as the secret key. In this paper, we propose a cross-modality SIBE (CM-SIBE) approach by employing deep learning. We construct two encryption schemes: a real SIBE (R-SIBE) and a virtual SIBE (V-SIBE). For convenience, their corresponding ciphertexts and PSFs are denoted as R-Ciphertext and R-PSF for the real scheme, and V-Ciphertext and V-PSF for the virtual one, respectively. We encrypt the plaintext with the R-SIBE and take the R-Ciphertext as the final ciphertext. However, we take the V-PSF as the secret key. For successful decryption, we train a DNN to convert the R-Ciphertext into its corresponding V-Ciphertext; the two ciphertexts are derived from the same plaintext. It is important to note that the V-PSF acts as the sole secret key, while the DNN serves as an auxiliary tool. For decryption, an authorized user first transforms the ciphertext into the V-Ciphertext using the DNN. Subsequently, the user deconvolves the V-Ciphertext with the V-PSF to retrieve the original plaintext. Our CM-SIBE ensures high-quality decryption of large-sized plaintexts that surpass the OME limit of the diffuser, while also circumventing the need for a bulky DNN as the secret key. Furthermore, our method is robust against known ciphertext-only (COA), while also demonstrating high resilience to noise and occlusion.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132926"},"PeriodicalIF":2.5,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.optcom.2026.132924
Lixun Sun , Yanxiong Yang , Yuyang Xiao , Yuquan Zhang , Xiaocong Yuan , Ting Mei
Extending the low-loss polariton response of graphene into the visible waveband is of significant interest for advancing applications in nanophotonics and optoelectronics. However, the challenge arises from the relatively low conductivity of graphene in this regime when coupled with common material properties. We reveal that a promising solution involves understanding and optimizing the influence of the dielectric environment on polariton excitation. In this work, both theoretical prediction and experimental evidence are presented, confirming the existence of transverse-electric surface polaritons in graphene within the visible waveband. This discovery is grounded in the optical admittance matching condition, providing a practical approach for achieving complete conversion of excitation photons into surface polaritons at designated wavelengths and incidence angles. By ensuring precise wavevector matching, the polaritons supported by structures specifically optimized for admittance matching exhibit theoretically attenuation-free propagation characteristics. This advancement holds promise for developing ultralow-loss polaritonic devices in the visible and near-infrared ranges.
{"title":"Perfect excitation of graphene surface polaritons in visible waveband","authors":"Lixun Sun , Yanxiong Yang , Yuyang Xiao , Yuquan Zhang , Xiaocong Yuan , Ting Mei","doi":"10.1016/j.optcom.2026.132924","DOIUrl":"10.1016/j.optcom.2026.132924","url":null,"abstract":"<div><div>Extending the low-loss polariton response of graphene into the visible waveband is of significant interest for advancing applications in nanophotonics and optoelectronics. However, the challenge arises from the relatively low conductivity of graphene in this regime when coupled with common material properties. We reveal that a promising solution involves understanding and optimizing the influence of the dielectric environment on polariton excitation. In this work, both theoretical prediction and experimental evidence are presented, confirming the existence of transverse-electric surface polaritons in graphene within the visible waveband. This discovery is grounded in the optical admittance matching condition, providing a practical approach for achieving complete conversion of excitation photons into surface polaritons at designated wavelengths and incidence angles. By ensuring precise wavevector matching, the polaritons supported by structures specifically optimized for admittance matching exhibit theoretically attenuation-free propagation characteristics. This advancement holds promise for developing ultralow-loss polaritonic devices in the visible and near-infrared ranges.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"607 ","pages":"Article 132924"},"PeriodicalIF":2.5,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.optcom.2026.132923
Anita Kumari, Vishwa Pal
We present a combined experimental and numerical study on the abrupt autofocusing and scintillation dynamics of truncated circular Airy derivative beams (CADBs) in free space and in strong turbulence. Inner and outer truncations of up to 60% are applied to investigate the impact of structural modifications on beam propagation. The autofocusing strength, quantified by the maximum K-value, is found to decrease systematically with increasing truncation. Inner truncation maintains higher maximum K-value but demonstrated increased sensitivity to turbulence. In contrast, outer truncation yields lower maximum K-value while offering enhanced robustness under turbulent conditions. Despite strong turbulence, all truncated CADBs exhibit a notable rise in their K-value, confirming the resilience of their intrinsic self-accelerating autofocusing behaviour. Further, scintillation index analysis reveal that self-healing governs turbulence response: inner truncation delays but intensifies scintillation due to core reconstruction, whereas outer truncation allows faster stabilization with reduced fluctuations. These results highlight truncation as a tunable parameter for balancing focusing strength and turbulence robustness, with relevance to free-space optical communication, imaging, and optical trapping.
{"title":"Abrupt autofocusing and scintillation dynamics of truncated circular airy derivative beams in strong turbulence","authors":"Anita Kumari, Vishwa Pal","doi":"10.1016/j.optcom.2026.132923","DOIUrl":"10.1016/j.optcom.2026.132923","url":null,"abstract":"<div><div>We present a combined experimental and numerical study on the abrupt autofocusing and scintillation dynamics of truncated circular Airy derivative beams (CADBs) in free space and in strong turbulence. Inner and outer truncations of up to 60% are applied to investigate the impact of structural modifications on beam propagation. The autofocusing strength, quantified by the maximum K-value, is found to decrease systematically with increasing truncation. Inner truncation maintains higher maximum K-value but demonstrated increased sensitivity to turbulence. In contrast, outer truncation yields lower maximum K-value while offering enhanced robustness under turbulent conditions. Despite strong turbulence, all truncated CADBs exhibit a notable rise in their K-value, confirming the resilience of their intrinsic self-accelerating autofocusing behaviour. Further, scintillation index analysis reveal that self-healing governs turbulence response: inner truncation delays but intensifies scintillation due to core reconstruction, whereas outer truncation allows faster stabilization with reduced fluctuations. These results highlight truncation as a tunable parameter for balancing focusing strength and turbulence robustness, with relevance to free-space optical communication, imaging, and optical trapping.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"607 ","pages":"Article 132923"},"PeriodicalIF":2.5,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.optcom.2026.132920
Jeonghun Seong , Jaehyeon Lim , Gibeen Gu , Taewon Kim , Hyeokin Kang , Sunghun Lee , Wooseok Park , Hyosang Yoon , Young-Jin Kim
Atmospheric effects degrade the performance of free-space optical links, which has prompted extensive research over several decades. Most studies have focused on scintillation, which describes the fluctuation in received optical power at the receiver. Meanwhile, the beam wander (BW) and angle-of-arrival (AoA) fluctuations are two factors that directly impact the position and angular movement of the optical beam in free-space. These effects are especially crucial for single-mode fiber-coupled free-space optical (FSO) communication systems to achieve high bandwidth and large-capacity data transmission via well-established fiber-optic communication components. However, despite their significance, detailed studies on BW and AoA fluctuations have not been addressed. In this study, we present a real-time monitoring system capable of simultaneously measuring the BW and AoA fluctuations with high precision using a single commercial camera; the system achieves a positional resolution within 80 μm (RMSE: 30.2 μm) and an angular resolution of 80 μrad (RMSE: 20.6 μrad). The atmospheric effects were evaluated using a collimated beam at 635 nm wavelength and 2.5 mW output power over a round-trip link of 130 m. The experimental results demonstrate that BW and AoA fluctuations exhibit dispersive probabilistic distributions depending on the strength of optical turbulence expressed with Cn2. Notably, the correlation of the beam centroid and AoA in both x- and y-directions moved with correlation coefficients between −0.72 and + 0.82. This work clarifies the necessity of distinguishing the two atmospheric effects (BW and AoA) and our findings offer valuable insights for optimizing the single-mode fiber-coupled FSO communication systems and high-precision laser-directed systems.
{"title":"Real-time monitoring of beam wander and angle-of-arrival fluctuation under atmospheric turbulence for efficient laser coupling to single-mode optical fibers","authors":"Jeonghun Seong , Jaehyeon Lim , Gibeen Gu , Taewon Kim , Hyeokin Kang , Sunghun Lee , Wooseok Park , Hyosang Yoon , Young-Jin Kim","doi":"10.1016/j.optcom.2026.132920","DOIUrl":"10.1016/j.optcom.2026.132920","url":null,"abstract":"<div><div>Atmospheric effects degrade the performance of free-space optical links, which has prompted extensive research over several decades. Most studies have focused on scintillation, which describes the fluctuation in received optical power at the receiver. Meanwhile, the beam wander (BW) and angle-of-arrival (AoA) fluctuations are two factors that directly impact the position and angular movement of the optical beam in free-space. These effects are especially crucial for single-mode fiber-coupled free-space optical (FSO) communication systems to achieve high bandwidth and large-capacity data transmission via well-established fiber-optic communication components. However, despite their significance, detailed studies on BW and AoA fluctuations have not been addressed. In this study, we present a real-time monitoring system capable of simultaneously measuring the BW and AoA fluctuations with high precision using a single commercial camera; the system achieves a positional resolution within 80 μm (RMSE: 30.2 μm) and an angular resolution of 80 μrad (RMSE: 20.6 μrad). The atmospheric effects were evaluated using a collimated beam at 635 nm wavelength and 2.5 mW output power over a round-trip link of 130 m. The experimental results demonstrate that BW and AoA fluctuations exhibit dispersive probabilistic distributions depending on the strength of optical turbulence expressed with <em>C</em><sub><em>n</em></sub><sup><em>2</em></sup>. Notably, the correlation of the beam centroid and AoA in both x- and y-directions moved with correlation coefficients between −0.72 and + 0.82. This work clarifies the necessity of distinguishing the two atmospheric effects (BW and AoA) and our findings offer valuable insights for optimizing the single-mode fiber-coupled FSO communication systems and high-precision laser-directed systems.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"607 ","pages":"Article 132920"},"PeriodicalIF":2.5,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.optcom.2026.132921
Shubin Hua , Ning Zhang , Yina Hai , Deqiang Ding , Peng Yin , Zhaolong He , Fangyu Sun , Huidong Guo , Wenda Shao
To enhance the concentration efficiency and space utilization of the concentrator, a stepped integrated photovoltaic concentrating system without Light Leakage has been developed. The interrelationships between the geometric concentration ratio, parabolic coefficient, light guide plate (LGP) step height, and the height of the outermost concentrating module have been thoroughly investigated. To address the issue of light leakage caused by the low acceptance angle after light coupling into the LGP, a design method for a stepped leak-proof light guide plate has been proposed. Considering the solar divergence angle, Fresnel losses, and material absorption, LightTools optical simulation software was used to trace the light rays of the designed system, revealing the impact of the LGP step height, the height of the outermost concentrating module, and the acceptance half-angle on the system's optical efficiency. The simulation results show that, when the step height is 0.1 cm, the geometric concentration ratio reaches 306, with a concentration efficiency of 64.70 %. When the step height increases to 0.5 cm, the geometric concentration ratio decreases to 62, while the concentration efficiency increases to 83.62 %. Additionally, as the axial error increases from 0° to 0.3°, the average energy flux density decreases from 7011.37 W/m2 to 6320.74 W/m2, with the concentrator efficiency reaching approximately 90.14 % of the peak value. In contrast, as the alignment error increases from 0° to 0.3°, the average energy flux density decreases from 7011.37 W/m2 to 6674.62 W/m2, and the concentrator efficiency reaches approximately 95.1 % of the peak value. Experimental results indicate that the designed concentrator achieves a peak concentration efficiency of 55.8 % at noon.
{"title":"The design method of stepped integrated photovoltaic concentrator without light leakage","authors":"Shubin Hua , Ning Zhang , Yina Hai , Deqiang Ding , Peng Yin , Zhaolong He , Fangyu Sun , Huidong Guo , Wenda Shao","doi":"10.1016/j.optcom.2026.132921","DOIUrl":"10.1016/j.optcom.2026.132921","url":null,"abstract":"<div><div>To enhance the concentration efficiency and space utilization of the concentrator, a stepped integrated photovoltaic concentrating system without Light Leakage has been developed. The interrelationships between the geometric concentration ratio, parabolic coefficient, light guide plate (LGP) step height, and the height of the outermost concentrating module have been thoroughly investigated. To address the issue of light leakage caused by the low acceptance angle after light coupling into the LGP, a design method for a stepped leak-proof light guide plate has been proposed. Considering the solar divergence angle, Fresnel losses, and material absorption, LightTools optical simulation software was used to trace the light rays of the designed system, revealing the impact of the LGP step height, the height of the outermost concentrating module, and the acceptance half-angle on the system's optical efficiency. The simulation results show that, when the step height is 0.1 cm, the geometric concentration ratio reaches 306, with a concentration efficiency of 64.70 %. When the step height increases to 0.5 cm, the geometric concentration ratio decreases to 62, while the concentration efficiency increases to 83.62 %. Additionally, as the axial error increases from 0° to 0.3°, the average energy flux density decreases from 7011.37 W/m<sup>2</sup> to 6320.74 W/m<sup>2</sup>, with the concentrator efficiency reaching approximately 90.14 % of the peak value. In contrast, as the alignment error increases from 0° to 0.3°, the average energy flux density decreases from 7011.37 W/m<sup>2</sup> to 6674.62 W/m<sup>2</sup>, and the concentrator efficiency reaches approximately 95.1 % of the peak value. Experimental results indicate that the designed concentrator achieves a peak concentration efficiency of 55.8 % at noon.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"607 ","pages":"Article 132921"},"PeriodicalIF":2.5,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15DOI: 10.1016/j.optcom.2026.132910
Chon-Fai Kam
We investigate classical nonlinear optical analogues of excited-state quantum phase transitions (ESQPTs) within a squeezing-enhanced generalized Lipkin–Meshkov–Glick (LMG) model, focusing on polarization dynamics in optical fibers with tetragonal symmetry. Through systematic mapping of coupled-mode equations across crystal symmetries, we identify a novel non-conventional squeezing term that induces classical bifurcations—even without a linear rotor term. These bifurcations, analyzed in detail on the Poincaré sphere, correspond—via established semiclassical correspondence—to singularities in excited-state spectra characteristic of ESQPTs in the quantum LMG counterpart. Our findings highlight deep classical–quantum interplay in optical systems, providing a controllable room-temperature platform for simulating mean-field limits of many-body quantum criticality, with potential applications in quantum metrology and simulation. Full quantum spectral analysis is deferred to future work.
{"title":"Classical optical analogues of excited-state quantum phase transitions in a squeezing-enhanced generalized Lipkin–Meshkov–Glick model","authors":"Chon-Fai Kam","doi":"10.1016/j.optcom.2026.132910","DOIUrl":"10.1016/j.optcom.2026.132910","url":null,"abstract":"<div><div>We investigate classical nonlinear optical analogues of excited-state quantum phase transitions (ESQPTs) within a squeezing-enhanced generalized Lipkin–Meshkov–Glick (LMG) model, focusing on polarization dynamics in optical fibers with tetragonal symmetry. Through systematic mapping of coupled-mode equations across crystal symmetries, we identify a novel non-conventional squeezing term that induces classical bifurcations—even without a linear rotor term. These bifurcations, analyzed in detail on the Poincaré sphere, correspond—via established semiclassical correspondence—to singularities in excited-state spectra characteristic of ESQPTs in the quantum LMG counterpart. Our findings highlight deep classical–quantum interplay in optical systems, providing a controllable room-temperature platform for simulating mean-field limits of many-body quantum criticality, with potential applications in quantum metrology and simulation. Full quantum spectral analysis is deferred to future work.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132910"},"PeriodicalIF":2.5,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15DOI: 10.1016/j.optcom.2026.132913
Wenxuan Pei, Zhen Zhou, Xinyu Li, Yang Lu, Wentao Li, Anxu Huang, Di Feng, Hongchen Jiao, Lishuang Feng
We present a polarization-insensitive electro-optic Mach-Zehnder modulator on a thin-film lithium niobate and silicon nitride heterogeneous integration platform. The design employs a Mach-Zehnder interferometer structure with integrated polarization rotators at the midpoint of each arm, enabling bidirectional TE0/TM0 mode conversion. This symmetric configuration ensures equal modulation efficiency for both polarization states, achieving polarization-insensitive operation. Through finite-difference time-domain and finite-element method simulations, we optimize the device design and evaluate its performance. The simulation results show identical modulation efficiency and comparable insertion loss for both polarization states. The proposed modulator is well-suited for optical communication systems and data centers, where polarization-insensitive operation is essential.
{"title":"Polarization-insensitive electro-optic mach-zehnder modulator on thin-film lithium niobate-silicon nitride heterogeneous platform","authors":"Wenxuan Pei, Zhen Zhou, Xinyu Li, Yang Lu, Wentao Li, Anxu Huang, Di Feng, Hongchen Jiao, Lishuang Feng","doi":"10.1016/j.optcom.2026.132913","DOIUrl":"10.1016/j.optcom.2026.132913","url":null,"abstract":"<div><div>We present a polarization-insensitive electro-optic Mach-Zehnder modulator on a thin-film lithium niobate and silicon nitride heterogeneous integration platform. The design employs a Mach-Zehnder interferometer structure with integrated polarization rotators at the midpoint of each arm, enabling bidirectional TE<sub>0</sub>/TM<sub>0</sub> mode conversion. This symmetric configuration ensures equal modulation efficiency for both polarization states, achieving polarization-insensitive operation. Through finite-difference time-domain and finite-element method simulations, we optimize the device design and evaluate its performance. The simulation results show identical modulation efficiency and comparable insertion loss for both polarization states. The proposed modulator is well-suited for optical communication systems and data centers, where polarization-insensitive operation is essential.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132913"},"PeriodicalIF":2.5,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-14DOI: 10.1016/j.optcom.2026.132895
Haoxin Tian , Hanyu Zhan , David Voelz , Lejun Chen , Jizhou Lai
The Fried parameter and coherence radius are two fundamental measures that characterize the spatial resolution effects of atmospheric turbulence on optical propagation and imaging. Here, their calculations for spherical and plane waves in von Karman turbulence are theoretical developed that includes the effects of both nonzero inner scale and finite outer scale. The simple analytic expressions are also derived for making the results easy to use. Then the split-step wave optics simulations are performed for modeling the long-exposure point spread function and mutual coherence function through von Karman turbulence for comparison. The expressions and numerical results agree well throughout the weak to strong turbulent scattering regimes.
{"title":"Long-exposure fried parameter and coherence radius through von Karman atmospheric turbulence","authors":"Haoxin Tian , Hanyu Zhan , David Voelz , Lejun Chen , Jizhou Lai","doi":"10.1016/j.optcom.2026.132895","DOIUrl":"10.1016/j.optcom.2026.132895","url":null,"abstract":"<div><div>The Fried parameter and coherence radius are two fundamental measures that characterize the spatial resolution effects of atmospheric turbulence on optical propagation and imaging. Here, their calculations for spherical and plane waves in von Karman turbulence are theoretical developed that includes the effects of both nonzero inner scale and finite outer scale. The simple analytic expressions are also derived for making the results easy to use. Then the split-step wave optics simulations are performed for modeling the long-exposure point spread function and mutual coherence function through von Karman turbulence for comparison. The expressions and numerical results agree well throughout the weak to strong turbulent scattering regimes.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"607 ","pages":"Article 132895"},"PeriodicalIF":2.5,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145996208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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